For many years, network technology has enabled the sharing of, and remote access to, computing resources around the world. One computer can readily exchange data with a computer down the hall or in another country. Of course, it did not take long for the business world to harness the power of global networks, and network technology has fueled the growth of an entire new industry focused on delivering services across these networks.
This new industry must be able to anticipate and meet customers' processing needs their requirements grow, while maximizing existing resources. One method of maximizing resources is to allow customers to share computing and networking resources. In one implementation of this method, a service provider creates “logical” partitions of computing resources on primary processing units (commonly known as “mainframe” computers). Discrete units of processing capacity within such a shared, on-demand environment are referred to herein as “engines.” Typically, a service provider contracts with several customers to provide a certain level of service to each customer, and creates or assigns a logical partition (LPAR) of resources to each customer to fulfill its obligations. One or more of the contracts, though, may allow for a margin of increase in the event of high peak usage. In the event of high usage by one customer, then, the service provider must be able to provide additional resources to that customer without adversely affecting any other customer resource utilization. To provide these additional resources, the service provider may re-allocate computing resources among various logical partitions until the customer's usage returns to normal. Allowing customers to share resources, though, requires the service provider to balance and monitor the shared resources carefully, so that the provider can meet all service obligations.
As new customers subscribe to the on-demand service, capacity planners also must ensure that the service provider has sufficient resource capacity for every customer. Excess resource capacity available to meet on-demand customer requirements is referred to as the “free pool.” Capacity planners also frequently set target levels of LPAR utilization. LPAR utilization is expressed as the ratio of engines in use to the number of engines available for use, usually expressed as a percentage of total capacity. There are two goals of LPAR utilization targets: to provide resources necessary to meet unexpected increases in customer demands, and to avoid wasting resources in the face of unexpectedly low customer demands.
Existing methods of on-demand free pool capacity planning involve using mathematical or statistical models to forecast resource usage for incoming customers. Capacity is increased by adding engines to meet the anticipated needs of each new customer. The current capacity planning methods add capacity in direct relation to the anticipated needs of each new customer. Because capacity planning projections are based on partial or estimated data, the projections are historically inaccurate. Further, existing capacity planning methods do not account for effects of more than one customer on capacity at any given time. For example, current planning techniques do not account for multiple customers simultaneously using more than their anticipated capacity.
Thus, a need exists in the art for an improved method and system of estimating the size of a free pool of resources necessary to meet service obligations.